Biological Detection And Strain Identification Of Soybean Mosaic Virus As Well As Mapping Resistance Gene Of Soybeans In Huang-Huai Region

Soybean mosaic virus (SMV), a global soybean disease, causes serious yield losses and quality decrease in soybeans. Two problems, strains identification and soybean resistance to SMV strains, need to be solved in Huang-Huai regions where summer soybean was mainly planted. In our study, specimens of soybean virus, collected from Huang-Huai regions, were examined and the method of examining SMV was improved on, and strains SMV identification was also completed. Inheritance and genetic mapping of resistance to SC-7, a strain with high virulence in Huang-Huai region, were also investigated. The main results are given as follows:1) 591 specimens of soybean leaves were collected and purified, among which fifty-two positive isolates were acquired. The application of direct tissue blotting immunoassay (DTBIA) and RT-PCR were explored to find a rapid system for detecting SMV. Fifty SMV specimens and nine positive RT-PCR products were acquired.2) Based on the response to ten identification hosts screened by Wang Xiuqiang and Yangyalin, fifty isolates were identified into seven strain groups as SC-3 ~ SC-9. According to the results from 1998 to 2002, the main strain groups in this area were SC-3 and SC-7. The analysis of distribution of strain groups suggested that SC-7 and SC-9 were the main strains groups in Anhui province. Strain groups in Henan province were mainly composed of SC-3, SC-4, SC-5 and SC-7. SC-3 and SC-7 were the main strains groups in Jiangsu province. Only four strains, SC-1, SC-3, SC-4 and SC-8 were found in Shandong province, and SC-3 was the main strain group. Furthermore, a new strain group SC-10, including AH2002, AH2034 and JS2134, was also identified. The difference between SC-9 and SC-10 is that SC-9 can infect Kwanggyo, but SC-10 cannot.3) Segregation ratios of resistant plants to susceptible plants in PI, P2, FI, and RIL populations of the cross between Kefeng No. 1 and Nannong 1138-2 were investigated after inoculated with SC-7 of SMV. The results indicated that the resistance to SC-7 in Kefeng No. 1 was controlled by a single dominant gene assigned the gene symbol as Rsc-7, With linkage analysis, the gene Rsc-7 was located on the linkage group N8-Dlb+W and linked with three of five resistance gene and a maker, The order and genetic distance were Rsa 30.6cM Rsc-7 22.1cM Rn3 10.3cM Rnl 15.8cMLC5T.